Inventor of the present invention developed the stirring-processing apparatus shown in Patent Documents 1 and 2, wherein a stirring chamber is immersed in a fluid thereby applying a shear force to the said fluid. In addition, as shown in Patent Document 3, various methods to produce a toner by using this apparatus have been proposed.
This stirring-processing apparatus is provided with a stirring chamber which is disposed in a fluid to be processed and with a rotating blade which is disposed in the said stirring chamber, wherein the stirring chamber is provided with a suction opening through which the fluid is sucked from outside into inside thereof by rotation of the rotating blade and with an ejecting opening through which the fluid is ejected from inside to outside thereof by rotation of the rotating blade, the both openings being disposed side by side in the direction of the axis of the rotating blade. In this apparatus, the rotating blade rotates at a high speed inside the stirring chamber, thereby carrying out the process of applying a shear force to the fluid. Especially, a screen rotates at a high speed in the opposite direction of the rotation direction of the rotating blade thereby applying the shear force to the fluid in a space formed with the rotating blade; and therefore, the fluid can be processed by such processes as emulsification, dispersion, and mixing.
However, there were some cases that the throughput expected by a designer could not be obtained. Inventor of the present invention investigated the reason for this, and then it was found that there are some cases that the suction flow of the fluid flowing into the suction opening from outside and the ejecting flow of the fluid ejected from the ejecting opening to outside interfere with each other, as a result, disturbing the flow of the suction flow into the suction opening, so that sufficient amount of the fluid cannot be introduced into the stirring chamber. Especially, this tendency appears eminently in a highly viscous fluid; and in such a case, there was even a case that a cavitation was formed around the suction opening.
In addition, in Patent Document 3, it is proposed that the difference between the angle formed between the introduction direction of the fluid into the stirring chamber and the rotation axis of the rotating blade and the angle between the discharge direction from the stirring chamber and the rotation axis of the rotating blade is made within the range of ±25 degrees. When the both angles are changed as mentioned above, there may be a case that the suction flow and the ejecting flow interfere with each other regardless of the viscosity.